llvd: add page (#8511)

* llvd: add page

* Update pages/linux/llvd.md

* Update llvd.md

* Change directory to common

pages/common/llvd.md

@@ -0,0 +1,20 @@
+# llvd
+
+> Linkedin Learning Video Downloader.
+> More information: <https://github.com/knowbee/llvd>.
+
+- Download a [c]ourse using cookie-based authentication:
+
+`llvd -c {{course-slug}} --cookies`
+
+- Download a course at a specific [r]esolution:
+
+`llvd -c {{course-slug}} -r 720`
+
+- Download a course with [ca]ptions (subtitles):
+
+`llvd -c {{course-slug}} --caption`
+
+- Download a course [p]ath with [t]hrottling between 10 to 30 seconds:
+
+`llvd -p {{path-slug}} -t {{10,30}} --cookies`